1. Field
The present application relates to gas turbines, and more particularly to a casing arrangement to improve component stiffness in a gas turbine, a casing arrangement to reduce operative vibrations, as well as a method to reduce critical panel mode response in a gas turbine casing and a method to reduce operative vibrations in a gas turbine casing.
2. Description of the Related Art
The turbine exhaust cylinder and the turbine exhaust manifold are coaxial gas turbine casing components connected together establishing a fluid flow path for the gas turbine exhaust. The fluid flow path includes an inner flow path and an outer flow path defined by an inner diameter delimiting an outer surface of the inner flow path and an outer diameter delimiting an inner surface of the outer flow path, respectively. Struts are arranged within the fluid flow path and serve several purposes such as supporting the inner and outer surfaces of the flow path and providing lubrication for the turbine and rotor bearing. The exhaust flow around the struts causes vibrations of the inner and outer diameter of the turbine exhaust cylinder and the turbine exhaust manifold due to vortex shedding. Vortex shedding are vibrations induced as the exhaust flows past the struts, where the struts partially obstruct the flow of the exhaust in the inner flow path. These vibrations are a potential contributor to damage occurring to the flow path of the turbine exhaust manifold and the turbine exhaust cylinder. This damage to the casing components may require early replacement or repair.